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NVD / CVE Program· CNA GitHub_M

CVE-2026-55192: FreeRDP: Out-of-bounds read in H.264 YUV-to-RGB conversion due to decoder/surface dimension mismatch

Noroxi assessment

Priority: Monitor (action score 28/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.45% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: FreeRDP FreeRDP 3.27.0.

Low priority for now. Upgrade to FreeRDP FreeRDP 3.27.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP H.264 decoder backends can return YUV planes sized from the bitstream without comparing the decoded width and height to the RDPGFX surface dimensions used to validate region rectangles. A malicious RDP server can provide an AVC420 or AVC444 bitstream whose decoded frame is smaller than the negotiated surface, causing yuv420_context_decode and the YUV-to-RGB conversion paths to read beyond the decoder-owned planes in libfreerdp/codec/h264.c and the selected H.264 backend. This can disclose client memory or crash the client. This issue is fixed in version 3.27.0.

HighCVSS 7.2 · v4.0—No exploit Fix available
Published
Aug 19, 2026
Updated
Oct 26, 2026
EPSS
0.4% · 39th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.2 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
7.2
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-55192

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
freerdpfreerdp

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • freerdp freerdpbefore 3.27.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • FreeRDP FreeRDP

    • < 3.27.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12freerdp2from 0—
Debian:13freerdp3from 0—
Debian:14freerdp3before 3.27.0+dfsg-13.27.0+dfsg-1
openSUSE:Tumbleweedfreerdpbefore 3.27.1-1.13.27.1-1.1
Red Hat:rhel_els:7freerdpbefore 0:2.1.1-5.el7_9.120:2.1.1-5.el7_9.12
Red Hat:rhel_els:7freerdp-debuginfobefore 0:2.1.1-5.el7_9.120:2.1.1-5.el7_9.12
Red Hat:rhel_els:7freerdp-develbefore 0:2.1.1-5.el7_9.120:2.1.1-5.el7_9.12
Red Hat:rhel_els:7freerdp-libsbefore 0:2.1.1-5.el7_9.120:2.1.1-5.el7_9.12
Red Hat:rhel_els:7libwinprbefore 0:2.1.1-5.el7_9.120:2.1.1-5.el7_9.12
Red Hat:rhel_els:7libwinpr-develbefore 0:2.1.1-5.el7_9.120:2.1.1-5.el7_9.12

Same product

freerdp: all records

Other highest-scoring records for the same primary product.

  • CVE-2018-8787FreeRDP prior to version 2.0.0-rc4 contains an Integer Overflow that leads to a Heap-Based Buffer Overflow in function gdi_Bitmap_Decompress
    42Plan
  • CVE-2018-8788FreeRDP prior to version 2.0.0-rc4 contains an Out-Of-Bounds Write of up to 4 bytes in function nsc_rle_decode() that results in a memory co
    41Plan
  • CVE-2018-8786FreeRDP prior to version 2.0.0-rc4 contains an Integer Truncation that leads to a Heap-Based Buffer Overflow in function update_read_bitmap_
    41Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-73242Aug 11, 2026 · FreeRDP: Kerberos GSS Wrap-token `EC` field is unbounded, causing an out-of-bounds decrypt in `kerberos_DecryptMessage`
    33Monitor
  • ← EarlierCVE-2026-55191Aug 19, 2026 · FreeRDP: Heap-buffer-overflow write in AVC444 YUV buffer allocation
    34Monitor
  • Later →CVE-2026-55193Aug 19, 2026 · FreeRDP: Heap-buffer-overflow write in TS Gateway RPC fragment receive due to uncapped bind_ack max_xmit_frag
    34Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
FreeRDP FreeRDP3.27.0 · descriptionVendor (CNA)
debian:freerdp33.27.0+dfsg-1 · Debian:14Package registry (OSV)
opensuse:freerdp3.27.1-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:freerdp0:2.1.1-5.el7_9.12 · Red Hat:rhel_els:7Package registry (OSV)
red hat:freerdp-debuginfo0:2.1.1-5.el7_9.12 · Red Hat:rhel_els:7Package registry (OSV)
red hat:freerdp-devel0:2.1.1-5.el7_9.12 · Red Hat:rhel_els:7Package registry (OSV)
red hat:freerdp-libs0:2.1.1-5.el7_9.12 · Red Hat:rhel_els:7Package registry (OSV)
red hat:libwinpr0:2.1.1-5.el7_9.12 · Red Hat:rhel_els:7Package registry (OSV)
red hat:libwinpr-devel0:2.1.1-5.el7_9.12 · Red Hat:rhel_els:7Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-31885159 days apartFreeRDP has an out-of-bounds read in ADPCM decoders due to missing predictor/step_index bounds checks
    37Monitor
  • CVE-2026-31897159 days apartFreeRDP has an out-of-bounds read in `freerdp_bitmap_decompress_planar`
    36Monitor
  • CVE-2026-6729018 days apartFreeRDP before 3.29.0 Heap Out-of-Bounds Read via TSMF
    34Monitor
  • CVE-2026-6729118 days apartFreeRDP before 3.29.0 Heap Out-of-Bounds Read via GLYPH_FRAGMENT_ADD
    34Monitor
  • CVE-2026-6730118 days apartFreeRDP before 3.29.0 Out-of-bounds Read via Polygon async message-proxy
    34Monitor
  • CVE-2026-33982142 days apartFreeRDP: Persistent Cache Allocator Mismatch - Heap OOB Read
    32Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
P
Scope
X

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records